Sealed joint for concrete slab road pavement



Nov. 13, 1951 J E, CARTER v 2,575,247

SEALED JOINT FOR CONCRETE SLAB ROAD PAVEMENT Filed May 18, 1946 3 Sheets-Sheet l 1111sl ATTORNEY:

Nov.v 13, 1951 J. E. CARTER SELED JOINT FOR CONCRETE SLAB ROAD PAVEMENT Filed May 1e, 194e 3 Sheets-Sheet 2 mma. n. n.

INVENTOR. Jolln 1E. ader RVZ/WW dm HIS ATTORNEYs NOV- 13, l951 J. E. CARTER SEALED JOINT FOR CONCRETE SLAB ROAD PAVEMENT s Sheng-sheet 5 Filed May 18, 1946 Fly. IZ

Fig. I5

L/0/1 BY 4 d H15 ATTORNEYS lNvENToR. E. Carter Vpoured around the dowel bars.

Patented Nov. 13, 1951 OFFICE SEALED JOINT 'FOR CONCRETE SLAB ROAD PAVEMENT John E. Carter, Columbus, Ohio Application May 1s, 1946, serial No. 670,791

(o1. :a4-fis) 8 Claims. Al

This invention relates to an improved sealed joint for concrete slab road pavement, and vpertains particularly to a construction using an elastomeric vand compressible joint sealing` strip, cooperable with dowel bars connecting the slabs, to forni a water-tight joint.

Concrete ,slab road construction using do-wel bar coupling oi the slabs to prevent tilting, requires the use of vertical joint sealing means, cooperating with the dowel bars, that lis Watertight Yduring expansion and contraction' movements of the slabs due to temperature changes Such sealing is necessary to prevent water erosion of' the road bed, ice damage to the concrete, and gradual disintegration of the pavement.

Heretofore, bituminous material has been used for a sealing medium as it normally is plastic, Weather resistant, and water-proof, and can be It is not, however, an elastomer nor is it compressible. The result is that, upon expansion of the slabs, the bituminous material is squeezed out into ridges on the surface of the road and becomes incorporated with foreign material which changes its plastic characteristics. Moreover, because it is not elastomeric, it does not return to its former shape, when the slabs contract, but leaves cracks between it and the vertical edges of the slabs, permitting water to enter. The consequence is, that the concrete of a newly laid road is almost immediately subject to weather damage which increases progressively.

Elastomeric strips, such as rubber strips, have been used instead of bituminous material, but such have been made of solid rubber, or its equivaient, which, as is well known, is elastically distortable but not compressible. That is, if it is deformed in one direction it undergoes a compensating distortion in another direction, the volume staying the same. In a compressed vertical joint, between road slabs, this distortion can only be in a vertical directionyand such a strip when subjected to squeezing, therefore, forms a ridge on the road surface subject to scuing by traffic, which disintegrates the strip.

I have provided a novel. joint sealing strip of elastomeric substance, such as natural rubber or rubber-like material, which has sealed air pockets or channels therein which permit compression of the strip without any substantial vertical` distortion of it, and which is adapted to cooperate inv sealed relation with elastomer covered dowel bars passing therethrough. Ihave combined the elastomeric characteristic of the strip with the compressbility characteristic .of an included .gas to: obtain my novel result. y K

My constructionalso provides easy means Vfor assembling the strip and protected dowel bars, in the road-bed, prior to pouring concrete thereover. l.

The novel .compressible elastomeric strip ymay be cut into desired lengths and sealed at the cut points to make the air pockets air-tight. l

In use,y in` a slab road constructiomthe strip permits the l.necessary expansion Aof. the slabs without any danger of water seeping into .the vertical joints, andwithoujt yany danger of the strip protruding above thel road surface tobesubjected there to the destructive scuiling' of road trafc. f A

Therefore, the principal object `of my invention is Yto provide an elastomeric and compressible vertical joint sealing strip for placementbetween concrete road slabs.

Another .object of the invention is to provide such a sealing strip having sealed air pockets'or channels therein.

Another object of the invention is to provide such a sealing strip'wi-th transverse holes Vtherein; for letting through dowel bars.

Another object of the invention is to provide suchv a sealing strip cooperable` with assembly devicesior maintaining theY stripl in` place on the roadbed, before concrete is poured thereover.

Another object of the invention is to providev an elastomeric covering for the dowel. bars that cooperates With the novel sealing strip to form a water-tight joint and to' protect the dowelbars of-my'invention is-illustrated i-n the az'zcompany-k ing drawings, formi-ngapartof this specication',1I

in-vwhich:

Fig. 1 isa perspective view, partlyin sectionV andr partly broken away, showing my invention in place ina concretef'slab pavement.

Fig. 2y isa vertical; section'. throughv Fig. 1y onthe line 2-2.

my novel' side plateusedinassembling the strip to'assembly" chairs.

Fig. 5 is a view in perspective of an assembly chair for holding the novel strip and side plates in place.

Fig. 6 is a perspective view of a dowel bar chair.

Fig. '1 is a view of a fastener for joining tw chairs such as the one shown in Fig. 6.

Fig. 8 is a modified form of a dowel bar chair.

Fig. 9 is a perspective view of a metalA strip on which to seat the joint sealing strip.

Fig. 10 is a perspective view of one of the plugs fitting the open ends of the elastomeric dowel bar covering tube shown in Fig. 11.

Fig. 11 is a perspective view of a dowel bar covering tube.

Fig. 12 is a perspective view of a dowel bar.

Fig. 13 shows the sealing strip with an end closure cemented thereto, and a corner support for the strip.

Fig. 14 is a tapered wedge pin for use in retaining the strip and side plates in the chairs.

Fig. 15 shows one of the chair fastening pins.

Fig. 16 is a modified form of the strip seat of Fig. 5.

In the drawings, the same reference numerals refer to the same parts throughout the several views, and the sectional view is taken looking in the direction of the arrows at the ends of the section line.

Fig. 1 shows a perspective view of a section of pavement including a concrete pavement slab f 20, an adjoining concrete slab 2 I, a vertical joint sealing strip 22 made of elastomeric material, dowel bars 23, 24, 25 and 26, covered with elastomeric material, piercing the strip 22 at intervals and held embedded in the concrete slabs 2l) and 2|. The concrete slabs 2u and 2| are cast upon a road base 21 which is in turn supported on a sub-base 28.

Prior to the casting of the concrete, the dowel bars and elastometric strips are assembled and held in position in a rigid framework construction so that their relative positions will not be affected by the distorting forces of the concrete caused by its pressure as it is cast rst on one side of a strip and then on the other side of a strip. The essential parts of this framework, as seen in Fig. 1, include a corrugated metal strip 21a positioned against one side of strip 22 with the corrugations running horizontally and a similar corrugated metal strip 28a placed against the other side of the strip in the same manner. The upper edge of each corrugated plate engages in a groove in the elastomeric strip provided for that purpose, said grooves 49 and 5B being shown best in Fig. 3. The elastomeric strip and supporting side plates rest on a metal strip 29 pinned to the road base 21 through pinning holes 30 (Fig. 9). The elastomeric strip and supporting side plates are pierced at intervals to permit to pass through it the dowel bars 23, 24, and 26 which are covered with an elastomeric casing having a snug water-tight fit. At intervals along the assembly of the elastomeric strip and side plates are chairs, such as chair 3| (see Fig. 5), having a nailing flange 32 and a toothed stripreceiving slot 33. Thechairs are pinned to the road base 21 through holes 34 by means of pins like pin 35. The teeth 33a in slot 33 are pointed downwardly so that any tendency of the strip and side plate assembly to move upwardly by the oating force of the concrete is thwarted. Upwardly projecting teeth 3S on the nailing flange engage the elastomeric strips bottom edge and prevent any horizontal displacement of the strip during the pouring of the concrete. Addirtop in-cross section.

tional bracing may be given to the strip at the ends thereof by angle plates, such as plate 31, a detail of which is shown in Fig. 13, one side of said angle plate lying against the side plate and strip and the other side of the angle plate lying along the side of one of the chairs.

Chairs are provided for the ends of the dowel bars. Chair 38, taken as an example, has a nailing flange 89, by which it is nailed to the road bed 21 by nails, such as nail 40. Each of these dowel bar chairs has two upright arms, each of which arms has therein a hole 4| (Fig. 6) for receiving an end of one of the covered dowel bars. Each of these dowel bar chairs cooperates with two of the dowel bars and, in order to form a more stable system, each dowel bar of those intermediate the outside one cooperates with two of the chairs. Thus, for instance, dowel bar 23 cooperates with chair 38 and chair 42 so thatthe right-hand arm of chair 38 (as seen in Fig. 1) and the left-hand arm of chair 42 both are engaged with covered dowel bar 23. Alternate chairs have their nailing iianges in the same direction but adjoining chairs have their nailing anges pointed in the opposite direction to enable a better fit of the two adjacent chairs. Each upright arm of the chair has two stapling holes 43 (Fig. `6) which, when adjoining chairs are in place, are in alignment, so that -a staple 44, such as is shown in Fig. 7, can be entered through the holes and the ears bent down to form a union of the two chairs. A modified single form of chair is shown in Fig. 8. Tapered pins, such as pin 45 (Fig. 14) may be used as a wedge between the corrugated metal side plates and the chair holding the strip in place, such tapered pins being shown in Fig. 1 at 45 and 46.

A typical pin for fastening the chairs to thev road bed is shown in Fig. 15.

Referring to Fig. 3, my novel elastomeric strip is shown having a narrower lower portion 41 and a top bead portion 48 which has a concave The bead on either side has grooves as explained, such as groove 49 and groove 5G, to receive the metal side plates. These grooves 49 and 59 are oir-set vertically so that the relation between corrugations of the side plates cause the side plates to be in nesting relation against the strip when pressed tightly against it. Running lengthwise of the strip are parallel air channels, such as channel 6|, which. have, roughly a heart-shaped cross section. As has been explained before, the strip has dowel bar apertures 62 through which the covered dowel bars may pass.

In Fig. 4 are shown the metal side plates with the corrugations and the holes 63 which are aligned with the holes 62 of the strip with which they are placed in contact.

Referring to Fig. 13, the cut end of a sealing strip is shown sealed by a solid strip 64 of the same material cemented thereto, so that the air pockets are sealed against entry of moisture, and against the expulsion of the air when the strip is compressed. Referring to Fig. 2 there is shown a cross section of a concrete embedded dowel bar covered with an elastomeric material. The

Adowel bar 65 (see, also Fig. 12) is encased in a tubular vestment of elastomeric substance, the tube 65 being somewhat longer than the dowel bar so as to leave at either end emptyspaees, such as spaces 61 and 61a.. The tube 56 is shown in detail in Fig. 11. Stoppers or plugs are fitted in either end of the tube, one of such Stoppers 58 being shown in detail Fig 10. Stopper B8 einen?? and Seals the .air channels lagainst entr-y ci, f

during-v hotperio'ds. exertpressureonine elast-c+. t

merio;` strip compressing the air in the airg, ellsl without any appreciable distortion off` the rubberupwardly. Any slight distortion of the rubber in a vertical direction will be takenup the concavi-ty along the top ofthe bead-of the strip Sothe no ridgeis` formed. above the level surface ofv ,the road.

In choosing an elastomer for use as a joint strip material` and as the vestment'of the dowel bar, I' prefer one-of the type-having the characterf isticsofA rubber; or rubber-like materia-l. Partlow. larly; additiontonatural rubber, I prefer the use/of the butadieneacrylonitrile copolymers. V-be-. cause of 'theirVV oil resistantV characteristi'cslandA generalv Agood behaviorunder all weather-V conditions.

I am aware that there are available many' kinds of elastomers, some of which have characteristics suitable for my purpose, and I am in no Way, therefore, insistingon the use of the greaseresistant butadiene copolymer type of synthetic rubber-like material, althoughthey are eminent-v ly suitable.

I prefer .thatmy 'elastomer has a tough resilience comparable to that found in automobile tires, and one that immediately reassumes-its normal shane after beingY distorted even; by-.as much as 100%. W I claim that under all ordinary weather con;- ditionsiny yjoint is vfar superior toany now known for-'waterproofing Vertical joints between concrete slabs 'andv that Vit will eifect marked improve;

ment in road construction by preventing. water and ice damage.

It*l will be apparent that because the corru-A gated side plates normallv meet the faces ofthe joint sealing strip at the high points ofthe ridges of the corrugations, there is considerable free space along the side surfaces of the'strin between it and the plates, where anv unusual excess of strip materiaLcaused byA distortion of the. strip. may be projected. VSnell a space lis being shown in Fig. 2,. This is. a, further-pro.- vision against the protrusion of rubber from the vertical joints of the road above the surface level thereof and is a further feature of my invention in combination with the concave treatment of the top of the strip.

I am aware that the structures herein described are susceptible of considerable variation without departing from the spirit of my invention, and, therefore, I claim mv invention broadly as indicated by the appended claims.

Having thus described my invention, what I desire to claim as new and useful is:

l. In a road construction adapted to be supported by and constructed on a road bed, in combination, a plurality of flat metal strips resting on said road bed; a plurality of internally channeled, water-proof elastomeric strips standing on .edfgeaone'onceaeih-z ofzv'sad :metal stripsfthe height of each otsaid-elastomericstrips being-the height of' athaintended pavement height. and -each Yof said. `strips, being.V slightly wider at the` top edge smdfhauingf'slightly below its top edge on either side va.ddwnwarclly openingfgroove iiushV witlrthe narrower part of: the strip and extending 'ups 'wardlyfi'ntozthe wider-` part of the strip a metal vsi'deplatelforeach. side of each ofA said'elastomericl'strips' each :plate extending thelength of the kvassociated strip and extending' downwardly 4trorng-i'n'si'de of thef'asso'ciated groovein the strip to the associated -metalstrip, said rsidelplates eachbeing'corrugated withthe corrugations para-lfl'el with the' road bed; means fa'stened'into the road-bedV at intervals for supporting each of said elastomeric strips4 and v assc'xziatefd meta-l slide plate '-iifn"verticalV position and in intimate water sea' drel'ation one another; a dowel bar pextedi'ngthrough apertures in each of saidelasstrips vand lassociated side plates at in; each-cf Saiddowel bars beine @Ove-rs by a water-proofA tube of' elastomeric material sealing'any ofv` the'internal channels in the elastomericls'tripsthat are opened by the dowel applugsin each. end of'each of said'dowel nar cgyerinss. to. lrnrevent seepage of water into thetubes llij.",spaced fromthe ends of thedOWQl bar; means associatedwith the endsof'thecovered doy/el bars for holding the same in paralleljalignmenta fixed distance off the road bed, said meansbeing fastened. v.to said road bed -and to each other toiorrn. arigid structure; and' cast concrete paving. sections on said roadv bed surrounding and 'covering said flat metal strips, dowelbarsf and-'dowel bar holding means, each paving sectionY etending .fro-m the metal plate engag-ingaon side-of one elastomeric strip to lthe metalvplatesengaging an opposite side of the next adiaeenftelastomeric strip, and from the road bedto the level of the tops of said elastomeric strips;

2. In ayjointed road-pavement construction, a sealingl joint-assembly comprising an elastomeric sealing stripv disposed edgewise in said pavement constructiomsad Sealing strip being formed with 'a'y plurality of*- ,ternalhorizontally-disposed channels .and havingv a transversely enlarged upner portion, also internally channeled horizontally, fon-niner abutments extending longitudinally along the sides of said strip near the upper edges, thereof; dowel openings formed Ythrough theA rimmeans for sealing any `of theinternal che-:Finals tha-tare opened by the dowerapertures, anda corrugatdtsde plate adjacent one ofthe Sid sof; said-sealing strin. and having its upper edgefln., engagement with one of said. abutments;

3. .In al joint/ed madpavementv construction, a sealing joint assembly comprising an elastomeric sealing strip disposed edgewise in the pavement construction, said sealing strip being formed with a plurality of internal horizontally disposed sealed air channels and having a transversely enlarged upper portion, also internally channeled horizontally, forming abutments on its sides near the upper edges thereof, the abutments on opposite sides 0f said strip being arranged at different levels heightwise of the strip, dowel openings formed through the strip, means for sealing any of the internal channels that are opened by the dowel apertures, and corrugated side plates on the road bed adjacent opposite sides of said sealing strip and having their upper edges in engagement with and overhung by said abutments with the corrugations of the respective plates arranged in nested juxtaposition.

4. In a jointed road pavement construction, a sealing joint assembly comprising a elastomeric sealing strip disposed edgewise in the pavement construction, said .elastomeric strip having VAi'n'- ternally thereof sealed air channels permitting horizontal compression without substantial vertical distortion of the strip, said strip having abutments extending along the sides thereof near thelupper edge, dowel apertures formed through the strip, means for sealing any' of the internal channels that are opened by the dowel apertures, and corrugated side plates on the roadbed adjacent opposite sides of said sealing strip -arid having their upper edges tting snugly against theunder side of said abutments.

5. In a jointed road pavement construction, -a sealing joint assembly comprising an elastomeric sealing strip disposed edgewise in the pavement construction, said sealing strip having internally thereof horizontally disposed sealed air channels and a transversely enlarged upper portion also internally channeled, formed on either side with a downwardly opening groove ilush with the narrower part of the strip and extending upwardly into the wider part near the upper edge of the strip, dowel apertures formed through the strip, means Vfor sealing any of the internal channels that are opened by the dowel apertures, and corrugated side plates on opposite sides of said sealing strip and liitting snugly into the grooves formed in the upper portion of said strip.

6. In a jointedv road pavement constructiOIl, a sealing joint assembly comprising an elastomeric sealing strip disposed edgewise in the pavement Construction, said sealing strip havinginternal sealed air channels and a transversely enlarged upper portion, also internally channeled, formed on either side with a downwardly opening groove flush with the narrower part of the strip and extending upwardly into the wider part, the grooves on opposite sides of the strip being arranged at dierent levels heightwise thereof, dowel apertures formed through the strip, means for sealing any of the internal channels that are opened by the dowel apertures, and corrugated side plates on opposite sides of said sealing strip and tting snugly within the grooves formed in the upper portion of said strip with the corrugations of said side plates arranged in nested juxtaposition.

7. In a jointed road pavement construction, a sealing joint assembly comprising an elastomeric sealing strip disposed edgewise in the pavement construction, said sealing strip being provided with an enlarged head and having internal sealed air channels permitting horizontal compression of said strip without substantial vertical distor- CTI tion thereof, said strip being formed with transversely extending apertures for receiving dowel bars, corrugated side plates on opposite sides of said sealing strip formed with dowel receiving apertures and having their upper edges abutting the under side of the enlarged head of the sealing strip, dowel bars extending through said sealing strip and side plate apertures, and sealing sleeves surrounding said dowel bars and extending through said apertures to seal said apertures and the air channels in said strip opening into said apertures.

8. In a jointed road pavement construction, a sealing joint assembly comprising an elastomeric sealing strip disposed edgewise in the pavement construction, said sealing strip having internal sealed air channels permitting horizontal compression of the strip without substantial vertica l distortion thereof, said strip being formed with transversely extending dowel bar receiving apertures, corrugated side plates adjacent the sides of said strip, said strip having projections extending transversely and sealing the space between the upper edges of said plates and said strip, said plates being formed with dowel bar receiving apertures aligned with the apertures in said strip, dowel bars extending transversely through said apertures, and elastomeric tubular oasings surrounding said dowel bars and extending through said apertures to seal the apertures and the channels in said strip opening into said apertures.

` JOHN E. CARTER.

REFERENCES CITED The followingr references are of record in the le of this patent:

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